OSK日本歌劇団 - Official Web Site of OSK (Japanese only)

OSK_SKD Community - Livejournal community for Japanese all-female theater troupes, including New OSK. Schedule information and news. (English and Japanese)

Shoujo Kageki - Moselle Green's Web Site on all-female stage troupes includes lots of interesting posters and program scans, as well as information. (English)

宝塚&OSK日本歌劇団共通ファン - A truly amazing amount of accumulated data and links relating to OSK and New OSK. (Japanese only)

ちどりん日記 - Lots of interesting posts about vintage OSK, as well as current New OSK happenings. (Japanese only)

大貴誠随喜館 - The rather eclectic site of a New OSK / Daiki Makoto fan. (Japanese only)

El angel de cereza - Ōka Noboru fan site (Japanese only) [It hasn't been updated in a while]